History 1: https://backpack.tf/item/6260230673

34 keys:

https://backpack.tf/profiles/76561198009010498#!/compare/1642204800/1642377600

https://backpack.tf/profiles/76561198261265788#!/compare/1642204800/1642291200

History 2: https://backpack.tf/item/6907855372

https://marketplace.tf/items/tf2/30897;5;u19

$65.99 / $1.78 = 37.07 keys ~37 keys

History 3: https://backpack.tf/item/10249687735

Dumped to a bot, 51.11 ref matches:

https://backpack.tf/profiles/76561198124296594#!/compare/1643328000/1643846400

https://backpack.tf/profiles/76561199013909713#!/compare/1643328000/1643414400

39 keys 21 ref ~39 keys:

https://backpack.tf/profiles/76561199013909713#!/compare/1643328000/1643414400

https://backpack.tf/profiles/76561198850003204#!/compare/1643328000/1643414400

History 4: https://backpack.tf/item/10610774337

Sold alongside Scorching Flames Field Practice and Stormy Storm Tartan Tyrolean, 153 keys match in buyer's compare:

https://backpack.tf/profiles/76561198453530349#!/compare/1637798400/1637884800

https://backpack.tf/profiles/76561198140316312#!/compare/1637798400/1637884800

Buyouts add up to 170 keys though

https://gladiator.tf/listings/619d992129d0415b12425ea7

https://gladiator.tf/listings/619e281ffa2f6ca6ec8a5280

https://gladiator.tf/listings/619d871bb4b99ca2aecb4628

The Shellmet's one is 38 keys though. Keys are missing but this sale should fall in-range with the other sales anyway

Sales at 34, 37, (38), 39

Buyers up to ~35 keys, not including 34

Taking 37-39 keys